Renewable fuse



W. U, SMHH.

RENEWABLE FUSE.

APPLICATWN man MAY28.1921.

Patented Nov. 28, 1922.

a citizen of the United States,

fuse link;

non-conducting material.

Patented Nov. 28, 1922.

IUNITED STATES PATENT OFFICE.

WALTER 0. SMITH, OF NEW BEDFORD, MASSACHUSETTS.

RENEWABLE FUSE.

Application filed May 28, 1921. Serial No. 473,248.

' To all whom it may concern:

Be it'known thatI, WALTER 0. SMITH, residing at New Bedford, in thecounty of Bristol and State of Massachusetts, have invented certain newand useful Improvements in Re newable Fuses, of which the following is aspecification.

This invention is an improved renewable fuse and has for its object theprovision of means whereby the fuse may be readily renewed when occasiondemands and in which a good electrical contact will be effectedbetween'the fuse link terminals and the fuse terminals. -A furtherobject of the invention' is to provide a simple and inexpensiveconstruction'by which access to the interior of the barrel will bepermitted when necessary and accumulated soot and other parti'clesmay beremoved. The invention also seeks to provide improved means forholdingthe ends of the fuse link against accidental or prematureseparation from the fuse terminals.

The invention is fully illustrated in the accompanying drawings, inwhich F igure 1 is a longitudinal section of a fuse illustrating oneembodiment of the invention Fig. 2 is a transverse 2-2 of Fig. 1; Fig. 3is a detail perspective view of the binder; 7 Fig. 4 is a detailperspective view of the section on the line Fig. 5 is a detailperspective view of the contact plate or disc.

Fig. 6 is a detail section showing another formof the invention;

" In carrying out my present invention, I employ a barrel 10 which ispreferably of fiber but,of course, may be of any other Upon each end ofthe barrel, I secure an internally threaded ferrule 11 which is of somegood conductor,

preferably copper or brass, the ferrules being threaded onto the ends ofthe barrel and then indented at one or more points, as indicated at 12,so that the threaded inner end of the ferrule will be partly mutilatedand a portion of the material of the ferrule embedded in the barrel. Theferrule will thus be permanently attached to the barrel, as will bereadily understood. I also employ a contact member 13 which ispreferably a circular plate or disc having threads or rounded so as toengage the longitudinal in its peripheral edge whereby it may be enatthe two ends of the barrel and the description herein given is aplicable equally to either end of the fuse. he tact plate is turned homein against the end Fig. 1, and it slot 14 having the end of the Theouter surface of the disc or plate is smooth, as shown at 16, so thatthe end of the fuse link may be bent against the same and form a perfectcontact therewith The fuse link is preferably a ribbon l7 weakenedmidway its ends, as shown at 18, and having its extremities bent inopposite directions, as shown at 19, when it is secured in place withinthe fuse. The edges or corners'20 of the slot 14 in the contact plate.are beveled avoid cutting the fuse link at said points and to facilitatethe insertion of the contact plate and also its removal, when removal isdesired, I provide the ferrule of the barrel, as shown in is providedwith a diametric flat walls 15 through which disc or confuse linkmay beinserted. y

notches 21 at the ends of the'slot which may 1 be engaged by a screwdriver or other turning tool in an obvious manner. To secure the ends ofthe fuse link in and against the contact plates, I employ a binder 22which may conveniently be stamped from sheet metal. This binder, asshown in Fig. 3, comprises a base portion 23 and a diametric ribor'projection 24 extending across the base portion and having its sidesnormally converging .toward its crown whereby I it is adapted to performthe functions of a wedge when inserted in the slot 14 of a contactmember 13. It will be readily noted that the projection or rib 24 isstruck up from the base portion 23 of the binder and will. 3

the edge .of the binder and the'internal As shown in Fig. 1,

threads of the ferrule. the sides of. the arched projection or rib 2%portion of the fuse link and have a wedging or clamping action thereonso that it is held to the side wall of the slot 14 and the base portionof the diameter binder bears against the outturned extremity of the fuselink and holds it in intimate contact with the outer fiat surface 16 ofthe contact member 13. 7 To retain the binder in operative position, Iemploy a follower in the form of a closure plug 25 which is threadedinto the ferrule and turned home against the base portion 5230f thebinder,

as clearly shown in Fig. 1, so that the binder will be positively andeffectually clamped between the plug and the contact member. As shown inFig. 1, the closure plug or follower "is provided with a central notch26 which may be utilized as a means of engagement with a turning tool soas to turn the plug home. Instead of the central notch, the plug may beprovided with eccentric notches or recesses to be engaged by aspanner.

In assemblmg the fuse, the ferrules are first threaded onto the ends ofthe barrel and the indentations formed therein so that the ferrulesbecome a permanent part of the device. The contact members 13am thenturned home in the ferrules so to abut-the ends of'the barrel and theparts ar so proportioned that, when the two contact members are fullyturned home, the slots 14 therein will register. The fuse link is theninserted through the ferrule at one end of the barrel and through theslot in the contact plate within said ferrule, the feeding of the linkbeing continued until the ad vance end thereof passes through the slot14 at the opposite end of the barrel. The eX- tremity of the link at oneend is then bent against the outer face of the adjacent contact memberand a binder is engaged in the slot 14- or said platc'and against theouter surface of said plate thereby clamping the end of the link, asshown in Fig. 1. The

follower or closure plug is then turned home against the base portion ofthe binder so that the binder will positively clamp the terminal of thefuse link into tight electrical connection with the contact member andthe binder will be clamped between the latter and the follower. Theoperation is then re peated at the opposite end of the fuse which willthen be complete and may be used in the usual manner.

The fuse shown and described is intended to be engaged and held byspring fingers or clamping members which form contacts in the electricconductor. If it be desired to apply the invention to fuses having knifeblade contacts, the knife blade 27 is formed on or secured to the binderso as to project therefrom in alinement with the arch of the same and acollar 28 is then threaded into the ferrule so that its inner end willbear upon the edge of the binder, which bears,

against the end of the fuse link and forces it into tight electricalconnection with the contact plate, said collar being provided with aflange 29 at its outer end to facilitate its manipulation and abut theouter end of the ferrule so as to limit the turning move ment of thecollar.

It will be readily seen that I have provided a very inexpensive fusewhich will be found. highly efficient in use. The engagement of the endof the fiber barrel against the contact plate will be strong enough tofrictionally resist turning of the contactplate so that the fuse cannotbe twisted when the outer plug is being tightened. This holding of thefuse link against twisting and consequent accidental rupture does notprevent a perfect contact between the end of the link and the contactmember being effected inasmuch as the binder is so constructed that itsnose or arched ribf projection willfit snugly within the flat-sided slotof the contact plate and its leaves will extend over the outer bentportion of the fuse link and hold it firmly against the contact memberand relative movement of the binder will be positively prevented. by theengagement of its nose within the contact member.

When a fuse blows, it is very common for particles of the metal to clingto the inside of the barrel and frequent blowing causes soot toaccumulate within the barrel. lVith my present construction access maybe had to the interior of the barrel to remove all such accumulationsand when a new fuse link has been inserted the fuse will be in perfectcondition. 7

Having thus described the invention, what is claimed as new is:

A fuse comprising a barrel, a ferrule fast on the end of the barrel,. acontact disc threaded into the ferrule and abutting the end of thebarrel, said disc having a fiatsided. diametric slot, a fuse linkextending through the barrel and having its terminal projecting throughthe slot in the adjacent contact disc, a binder disposed loosely withinthe ferrule at the outer sideiof the contact disc and having aflat-sided nose engaging within the slot of the, contact disc and basalleaves bearing against the outer face of the contact disc, the end ofthefuse link being held against one wall of said slot by the noseof thebinder and against the outer face of the disc by a basal leaf of thebinder, and means within the outer end of the ferrule to clamp thebinder against the outer face of the contact disc and the end of thefuse link.

In testimony whereof I affix my signature.

I wALTnno. SMITH. 1.8;

